Vibration switch



y 5, 1964 H. s. KACHLINE ETAL 3,132,221

VIBRATION SWITCH Filed Dec. 15, 1961 INVENTORS Harold S. Kachline 8 F'G'.2. John F. Waller ATTORNEY 1 device United States Patent 3,132,221 VRATHON SWITCH Harold S. Kaehline, Norristown, and John F. Waller, Philadelphia, Pa, assignors to Robertshaw Controls Company, a corporation of Delaware Filed Dec. 15, 1961, Ser. No. 159,645 8 Claims. (Cl. ZOO-61.53)

The present invention relates to vibration responsive means and more particularly to a vibration responsive switch.

. Briefiy,.this deviceis a when subjected normally closed switch, which to linear vibrations of a given frequency and amplitude, break-s an electrical circuit and accordingly one object of the present invention is to provide a means of sensing vibrations of a given magnitude and frequency.

Another object is to provide a switch for controlling an electrical circuit by maintaining the circuit closed below a preset level of vibrations.

Still another object is to provide a switch for opening and maintaining an electric circuit open by vibrations above a preset level.

Yet another object is to provide a vibration switch used to open or close -a circuit directly without the use of capacitors and/or relays. I 1

Other objects and advantages of the invention-will become apparent in the course of the following detailed description, taken inconnection .with the accompanying drawing, wherein;

FIGURE l illustrates one form of. the present invention in longitudinal cross section; and

FIGUREZ is a top plan view of the same.

Referringin detail to the drawing and first with partic ular reference to FIGURE 1, the present novel device consists of a casing 10, which is prsferably cylindrical. Within the casing cylinder 1h is a mass member, such as a piston 11 and a coil compression spring 12, which spring has the lower convolution 14 thereof engaged with the flat top surface of the piston 11 and the upper convolution 15 thereof engaged against a plate 16 formed with a central bleed port .17. g

The casing cylinder is countenbored at its respective lower and upper ends to provide an annular shoulder 19 at the lower end and an annular shoulder 20' at the upper end. For example, the lower end of the cylinder is sealed closed by a disc 2 2 which seats on the shoulder 19 and is held in place by staking or turning over the peripheral rim of the lower countenbored portion of the cylinder.

The disc 22 is formed of suitable insulating material and is centrally formed with an air exhaust port 23. Also, the disc 22 serves as a suppont for electric contacts or jacks 24 and 25.

Directly above the interior side of the disc 22 in the casing 1! is a dish-shaped disc 247 formed of suitable conducting material adapted to engage and disengage with the electric contacts 24 and 25 responsive to. preset vibration levels received in the device.

The dish-shaped disc 27 is formed with a center opening and is depended from the flat surfaced lower end of the piston :11 by means of a concentrically mounted de pending stud 28, which is formed with a head 29' to retain an insulated eyelet 30. The eyelet tits in the opening of the disc 27 andlalso on the stud above the disc 2'7 the stud carries an arcuate washer 30a, whereby the contact disc 27 is mounted to wobble about the fixed center point provided by the stud.

The casing 10 at the upper counterbored end confines therein the spring engaging plate '16, which seats on the annular shoulder 20. The plate 16 is held against the shoulder 20 by an end cap 31. The end cap 31 is cupshaped-and is cupped downwa-rdly so the rim 32 of the horn within the spring chamber 34 in 3,132,221 Patented May 5,1954

cup clamps the peripheral rim surface of a diaphragm 33 between said rim and the underlying peripheral surface of the upper side of the spring plate 16. The diaphragm on one-wayvalve means 33 includes an upstanding bead 35 formed with ports 36 and is responsive to pressure the casing 10 above the piston 11. The diaphragm ilexes to open and close the central opening or port '17 in the spring plate 16. Whenthe diaphragm serves as a one-way valve means and is moved to open posit-ion by air compressed in the chamber '34, air then bleeds from the chamber through opening '17 and diaphragm ports 36 to atmosphere through an exhaust port 37, in the cap 01.

The bore of the cylinder 1t} is slightly larger than the circumference of the piston :11 to provide a clearance therebetween, such as an annular air gap 31 between it and the cylinder bore for the purpose hereinafiter ex plained. As above described there is provided a chamber 34 above the piston 11, and also there is a chamber 39 below the piston 11, which chamber exhausts through port 23 at low level vibrations to close the switch contacts as will be explained hereinafter in detail under the heading Operation? Operation The contacts 24 and 25 are connected to a suitable electric circuit, which are normally bridged to switch closed position by the conducting disc 27 when the switch is at rest. For example, when the switch isat rest compres- If the switch device is subjected to vibrations along the longitudinal axis of casing 10, of sufiicient magnitude and frequency to overcome the force of compression spring 12, the piston 11 oscillates within the casing 10. During the resulting upward stroke of the piston 11, air is drawn into lower chamber 39 through port 23. The air in upper chamber 34 is compressed until the pressure is sufiicient to move diaphragm 33 away from port 17. Air then bleeds from upper chamber 34, through port 17, and diaphragm ports 36 to atmosphere through exhaust port 37.

Air continues to exhaust to atmosphere until the piston 11 reaches maximum height for a preset vibration level condition and the pressure in upper chamber 34 approaches atmospheric pressure. The diaphragm 33 then returns and closes port 17.

On the downward stroke of the piston 11, air in the lower chamber 39 is exhausted through port 23 to atmosphere, and air in upper chamber 34 drops below atmospheric pressure. The resulting differential pressure between upper and lower chambers 34 and 39 impedes and 25. The external circuit connected across contacts 24 and 25 is, therefore, maintained in an open position. When the external vibrations cease the force of compression spring 12 on-piston 11 is opposed by the differential pressure existing between chambers 34 and 39.

Air from chamber 39 slowly bleeds through clearance 31, into upper chamber 34. This action decreases the differential pressure across piston 11, and the compression spring 12, returns piston 11 to the extreme lower position, permitting conducting disc 27 to touch contacts 24 and 25, thereby closing the electrical circuit.

The preset level of the present novel device can be varied, if desired, by changing the mass of piston 11, the strength of the compression spring 12 and/ or the responpossible to employ sive action of the pressure diode on one-way valve 33 by varying the bleed port'size. Thus any adjustment in the spring rate, Weight of the piston, or both will cause the break point, G-level, oi the switch to,change', making it this device to sense'vibrationsat any frequency. l

Also, a'delay on make of the switch can be controlled byvaryin'g-the clearance 31'. 7

If desired, the entire unit'may be hermetically sealed by encapsulation with a'suitable dielectric'material, provided there. is an air path external to the casing 18. V

Without further description it is believed that the adbetween port 23 and port 37,

vantages of'the present invention over the prior art is apparent and while only one embodiment of the same is illustrated, it is to be expressly' understood that the same is not limited thereto a various changes may be made in the combination. and arrangement of the parts illustrated,

as will now likely appear to ot ers andthose skilled in the art. For a definition of the scope or limits of the invention,reference should behad to the appended claims.

What isclaimed is: r

l. A normally closed switch for controlling an electrical circuit comprising a casi g, a piston means oscillatable in the casing in response to preset levels of vibration, said piston carrying a switch conductor means, spring means biasing said piston and switchconductor means to closed circuit position, said piston dividing said casing intoupper and lower chambers, said casing having an opening in the lower end thereof communicating with said lower chamber, and said casing having a diaphragm controlled'exhaust valve in the upper chamber movable to open position by air compressed in said upper chamber.

2. Means responsive ,to'preset vibration levels comprising a casing, electriccontact means in the lower end of the casing, a movable mass in said casing, electric switch means secured to the lower side of said mass, a compression springengaged with seated in the upper end of said casing normally biasing said mass to the'circuit closing position of said switch means below said preset vibration levels, and one-Way valve means mounted in the upper end of said casing above said spring for bleeding air in response to air com pressed in said upper end of the casing by the upward switch open position of said mass in response set vibration levels. V V

'3. Means responsive to preset vibration levels as detosaid presaid easing into upper and lower chambers, a compression spring in the upper chamber biasing said mass toward the bottom of said lower chamber, circuit-connecting contacts at the bottom of said lower chamber, contact closing means carried by said mass in said lower chamber and engageable with said contacts, said lower chamber being closed at its lower end by an insulated disc for supporting said contacts, said disc having an air opening therein, and said upper chamber of the casing being provided with a one-way valve means actuatedin response to the air compressed in the upper chamber resulting from the movement of said mass. 7

' 6. The vibration responsive switch described in claim 5, wherein said one-way valve means comprises a centrally apertured plate, a flexible diaphragm with openings therein movable to open and close the central aperture in the plate, and an endretainer cap with an opening therein, said cap retaining said diaphragm in operative position, whereby movement of said mass to open switch position varies the pressure of the air in said upper chamber to raise said diaphragm above said plate aperture, to

thereby bleed air to atmosphere through said diaphragm openings and draw air into said lower chamber through said air opening in said disc;

V material, a pair of spaced contacts .of the "casing, said disc being loosely mounted in the the upper side of said mass and p linear vibrations along scribed in claim 2, whereinsaid casing is a cylinder and said mass is a piston. I V

4.. Means responsive to preset vibration levels as described in claim 2, wherein said mass is relatively smaller.

prising a casing, a movable mass in said casing dividing 7. A normally closed switch responsive to linear, vibrations or" a preset frequency and amplitude, comprising a casing, means responsive to saidyibrations to open said switch, and bias means for said vibration responsive means to maintain said switch closed against vibrations below said vibrations of preset frequency andamplitude, said switch including a dish-shaped disc of conducting mounted in the bottom lower. portion of said vibration responsive means on an insulated stud, whereby the said disc is free to wobble about'the fixation point provided by said stud and oneway pressure operated valve means at an end oi the casing, to thereby bleed air to the atmosphere;

8. A normally closed electric switch responsive to vibrations abovea preset level comprising a cylinder, a piston in said cylinder, said piston'being movable by the longitudinalaxis of said cylinder, pneumatically actuated one-way valve means responsive tothe movement of said piston, variable spring means controlling the vibration response level of said piston, conductor means carried by said piston, and spaced electric contact members mounted in the lower end of said cylinder connected by said conductormeans in the normallyclosed position of the switch.

2,835,759 'Waldow' May '20, 1958 2,839,777 Parsons lune 24, 1958 3,040,842 Charbonneau June 26, 19 62 

1. A NORMALLY CLOSED SWITCH FOR CONTROLLING AN ELECTRICAL CIRCUIT COMPRISING A CASING, A PISTON MEANS OSCILLATABLE IN THE CASING IN RESPONSE TO PRESET LEVELS OF VIBRATION, SAID PISTON CARRYING A SWITCH CONDUCTOR MEANS, SPRING MEANS BIASING SAID PISTON AND SWITCH CONDUCTOR MEANS TO CLOSED CIRCUIT POSITION, SAID PISTON DIVIDING SAID CASING INTO UPPER AND LOWER CHAMBERS, SAID CASING HAVING AN OPENING IN THE LOWER END THEREOF COMMUNICATING WITH SAID LOWER CHAMBER, AND SAID CASING HAVING A DIAPHRAGM CONTROLLED EXHAUST VALVE IN THE UPPER CHAMBER MOVABLE TO OPEN POSITION BY AIR COMPRESSED IN SAID UPPER CHAMBER. 